how to populate combobox based on another combobox's selected value

Hello Hazem,

look at ComboBox's events SelectedIndexChanged, SelectedValueChanged and the property SelectedItem. So when CB A has a selection change you
populate CB B appropriately.

Populating CB B:

comboBox1.Items.Clear();
comboBox1.Items.Add(new Item("Blue", 1));
...
...

Cheers

Manfred